【作者】 高婷；

【导师】 陈立国；

【作者基本信息】 华中农业大学 ， 微生物学， 2006， 硕士

【摘要】 分解者亚系统研究是搞清草原生态系统中能量流动和物质循环的关键环节，土壤微生物在亚系统中起着极为重要的作用。土壤微生物区系组成、数量都不同程度地与草原生态系统中的能量流动和物质转化过程有关。不同的草原植被类型、土壤质地、土壤养分条件及水分状态均影响着土壤微生物的区系组成和数量。这方面的研究对于退化草场的恢复和治理以及提高草原生产力均有重要的理论和实践意义。对宁夏干旱区灰钙土荒漠草原土壤微生物时空分布及其多样性研究表明，土壤微生物区系与草原植被类型、土壤质地密切相关，且相互制约。荒漠草原土壤微生物多样性研究表明，细菌有十二个属：芽孢杆菌属(Bacillus)、产碱菌属(Alcaligenes)、土壤杆菌属(Agrobacterium)、假单胞菌属(Pscudomonas)、欧文氏菌属(Erwinia)、肠杆菌属(Enterobacteriaceae)、节杆杆菌属(Arthrobacter)、黄单胞菌属(Xanthomonas)、黄杆菌属(Flavobacterium)、不动杆菌属(Acinetobacter)、棒杆菌属(Corynebacterium)及微球菌属(Miorococcus)。其中芽孢细菌的种类在轻壤土—植被类型④中比较多，紧沙土—植被类型①中几乎没有芽孢菌属，而假单胞菌属的种类较多，可初步得出：芽孢细菌适应在类型④中生长发育，而在类型①中则更利于假单胞细菌的生长发育；放线菌有九个属：链霉菌属(Atreptomyces)、链轮丝菌属(Streptoverticillium)、小单孢菌属(Micromonspora)、游动放线菌属(Actinoplanes)、游动单孢菌属(Planomonospora)、间孢囊菌属(Intrasporangium)、北里孢菌属(Kitasatosporia)、螺孢菌属(Spirillospra)、链孢囊菌属(Streptosporangium)。其中在类型①中放线菌的种类最多，有8个属，说明放线菌类更适应在碱性沙质土壤中生存，同时对改良退化草原土壤质量意义重大，可称其为治理沙漠的先锋菌类；真菌有七个属：青霉属(Penicillium)、曲霉属(Aspergillus)、头孢霉属(Cephalosporium Corda)、镰孢霉属(亦称镰刀霉)(Coniothecium)、芽枝霉属(Cladosporium)、交链孢霉属(Alternaria)、毛霉属(Mucor)。其中类型①中的真菌种类单一，只有青霉属，而在类型④中有7个属，初步显示：土壤质地较差、植被类型单一，真菌种类会随之减少，反之亦然。土壤微生物数量季节动态分布：细菌数量分布是秋季＞夏季＞春季；真菌数量分布是夏季＞秋季＞春季，夏季分别是秋季和春季的1.98倍和3.45倍；放线菌数量分布是秋季＞春季＞夏季。反映出土壤微生物各类群数量变化均有明显的季节变化特性，而且其数量分布明显受降雨量的影响。层化率研究表明：微生物数量层化比率为2.00可作为土壤质量评价的阈值。中壤土—植被类型②总菌数的层化率为2.31，表明土壤质量较好；类型④总菌数的层化率为2.00，表明土壤质量正值健康状态；类型①总菌数的层化率最低为0.66，各类菌层化率在0.87—5.08之间变异极大，表明类型①生态条件极端脆弱，土壤已向退化方向发展；沙壤土—植被类型③总菌数的层化率1.61，表明该植被型亦较差，必须对其进行人工修复，土壤质量方能向健康方向演替。研究提出：干旱贫瘠的荒漠草原在恢复与重建中，应以抗逆性强的能形成放线菌根瘤的草、树种如苦豆子、花棒等沙生豆科植物作为先锋植物。更多还原

【Abstract】 Research on the decomposer subsystem is the key link of clarifying the energy flow and the circulation of materials in the prairie ecosystem, the soil microorganism is playing the extremely vital role in the second ecosystem. The composition and quantity of soil microorganism in some degree are related to prairie ecosystem energy flow and the material transformation process. The composition and quantity of soil microorganism are affected by different prairie vegetation type, the soil texture, nutrition and moisture condition. The research on this aspect have a important theoretical and practical significance in the degenerated pasture restoration as well as enhancing the prairie productive forces.The research on the biodiversity, temporal and spatial distribution of soil microorganism in sierozem arid area wildemess prairie of Ningxia indicated that the soil microorganism area have a close correlationship with the prairie vegetation type and the soil texture, also restricts each other.The research of wildemess prairie soil microorganism biodiversity indicated that the 12 "genera" bacteria are: Bacillus、Alcaligenes、A grobacterium、Pscudomonas、Erwinia、Enterobacteriaceae、Arthrobacter、Xanthomonas、Flavobacterium、Acinetobacter、Corynebacterium and Miorococcus. There is quite a number of Bacillus in type(④, in type①there are no Bacillus nearly, but there are many Agrobacterium in this type, It can be concluded initially that: The Bacillus adapts growth in the type④, but in type①the Pscudomonas favors growth. The 9 "genera" actinomycetes are: Atreptomyces、Streptoverticillium、Micromonspora、Actinoplanes、Planomonospora、Intrasporangium、Kitasatosporia、Spirillospra、Streptosporangium. Most species of actinomycetes is in type①, and the "genera" are about 8. That is to say actinomycetes are more suitable to survive in the alkalinity sandy soil, simultaneously it has great significance to improve degenerated prairie soil quality, and it may be the main fungi for governing desert. The 7 "genera" fungi are: Penicillium, Aspergillus、Cephalosporium Corda、Coniothecium、Cladosporium、Alternaria、Mucor. There is a single genera fungi in type①, which is only belong to Penicillium, but in type④there are 7 genera. This demonstrated initially: When the soil texture is bad and the vegetation type is unitary, so the types of fungi will reduce and vice versa.The seasonal distribution in number of soil microorganism: The orderof seasonal distribution in number of bacteria is autumn＞summer＞spring; The order of seasonal distribution in number of fungi is summer＞autumn＞spring, the number in summer was 1.98 times as much as that in autumn and 3.45 times as much as that in spring; The order of seasonal distribution in number of actinomycetes is autumn＞spring＞summer. That reflects the quantity variation of each soil microorganism group has an obvious seasonal variation characteristic, moreover its quantity distribution obviously affected by the rainfall quantity.The stratification rate research indicated that: The microorganism quantity stratification ratio is 2.00 which may be used as the threshold value of soil quality appraisal. The total fungi quantity stratification rate of type is 2.31, indicated the soil quality is better; The total fungus stratification rate of type④is 2.00, indicated the soil quality just in its healthy conditions; The total fungi stratification rate of type①is the lowest about 0.66, each stratification rate of the variation is enormous between 0.87-5.08, which indicates the ecological condition is extremely frail of the type①, the soil has developed to the degenerated direction; The total fungi stratification rate of type③is 1.61, indicated this type of vegetation is also bad, the manual repair to it must be carried on, the succession of soil quality can be faced to the healthy direction.The research proposed that: In the process of restoring and reconstruction the arid barren wilderness prairie, those tree seed、grass like bitter bean and also the leguminous plant which can formate actinomycetes nodule fungi and have strong resistance ability should be the main plant.更多还原